X-rays are electromagnetic waves having a wavelength of about 0.01 Å to 100 Å. Since X-rays can pass through many materials, X-rays are widely used in medical devices for photographing inner organs of living bodies or industrial nondestructive inspection devices.
X-ray apparatuses may take X-ray images of an object by irradiating the object with X-rays emitted from an X-ray source and detecting the intensity difference between X-rays passing through the object using an X-ray detector. The inside structure of the object may be checked using the X-ray images, and then the object may be diagnosed. The inside structures of objects may easily be checked using X-ray apparatuses that operate on the principle that the transmittance of X-rays varies according to the densities of the objects and the atomic numbers of atoms constituting the objects. Short-wavelength X-rays have high transmittance and thus provide bright images.